1. Field of the Invention
The present invention relates to a torque sensor in which a multi-pole permanent magnet having a plurality of N poles and a plurality of S poles alternatingly arranged in the peripheral direction is fixed to one of a first shaft and a second shaft linked via a torsion bar, a first rotating yoke and a second rotating yoke each having provided at equal intervals in the peripheral direction a plurality of claw portions facing the permanent magnet are fixed to the other of the first shaft and the second shaft, and a magnetism detection element is disposed between a first magnetism-collecting yoke and a second magnetism-collecting yoke individually facing the first and second rotating yokes and, in particular, to an improvement of a torque sensor suitably used in an electric power steering system.
2. Description of the Related Art
A torque sensor in which a ring-shaped multi-pole magnet is fixed to a first shaft side linked to a second shaft via a torsion bar, and a pair of rotating yokes each having a claw portion facing the multi-pole magnet are fixed to the second shaft side, is known from Japanese Patent Application Laid-open No. 2008-180517.
However, in the arrangement disclosed by Japanese Patent Application Laid-open No. 2008-180517, since the pair of rotating yokes have different shapes from each other, it is necessary to produce two types of rotating yokes and, moreover, it is also necessary to produce two types of magnetism-collecting yokes, thereby resulting in an increase in production cost.